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Author: lkwalters

Now that the long awaited study on the pathologies of the holotype specimen (UCMP 37302) of Dilophosaurus wetherilli have been published, I can finally share this full illustration with all of you. This one did not make the final paper, but instead, an edited version of it did, surrounded by images of the fossil specimen and its pathologies.

To see a larger version of it, please visit the “Art Gallery” section of my website, which you can reach by expanding the menu. (To do this: click on the black box with white lines above my name at the top of this page).

This image has undergone a number of revisions since its initial version- most notably, the addition of well defined cast shadows on the sand, as well as deeper shadows on the D. wetherilli itself. This was done on the advice of a good artist friend of mine. I think the illustration looks much better now, although it could probably use some stronger highlights as well. As with the previous illustrations I did for Dr. Phil Senter, this one was also completed on a deadline.

You will also notice that Dr. Senter’s signature is on the image as well- that is because he was so kind as to provide me with the initial sketch of the pose he was envisioning for the Dilophosaurus, which I was having some trouble visualizing myself. I thank him a lot for the initial sketch, because the pose is very dynamic and even more eye-catching than the poses I had tried for the Dilophosaurus.

He also suggested that the image give the impression that the Diloph has been “stalking the viewer”: to create this feeling I illustrated the trail of its footprints in the sand behind it, and gave the eye a light coloration to emphasize the pupil. If you look closely, you’ll also see its nicitating membrane beginning to swipe over the eye.

I wanted to avoid as many “paleoart memes” as possible in this image. I tried to avoid the “platform” look that so many paleoartists do- which is putting the dinosaur on a flat landscape, also with all of its body visible. I couldn’t hide any of its body for the purposes of this drawing, but I was able to make the landscape sufficiently hilly. I also included a dead fern in it- that’s because in my opinion, it seems like every single plant is perfectly formed, alive, and flourishing in most paleoart pieces, even though in nature there are plenty of dead plants to be seen.

I also haven’t seen Dilophosaurus illustrated with solid, bright red crests very often: it’s almost always Allosaurus that falls prey to this meme thanks to Walking With Dinosaurs. I also attempted to make them look sufficiently thick with keratin, the way they most likely were in life, and even extended the keratin down to the front of the snout- but I admittedly do not know how plausible this is.

I also looked at Jaime Headden’s ( http://qilong.wordpress.com ) Dilophosaurus skull reconstruction, and used that as a reference for how to properly depict the crest.

It is also rare to see this species illustrated with feathers, so I decided to give it a speculative coat of Stage 2 -or even 3 (!) feathers. Yes, perhaps Stage 3 is a bit too speculative, but Currie & Chen’s 2001 re-examination of the feathers of Sinosauropteryx prima led me to the conclusion that maybe, just maybe, Stage 3 feathers could have appeared a lot earlier than once thought. Yes, this is still quite speculative, but I don’t think I’d be surprised if they do one day find a Dilophosaurus specimen with feathers that are this advanced.

The reddish coloration on the back of the neck was inspired by a Rufous-Necked Hornbill.

Enough explanation about my illustration, then, and on to why I think the research Dr. Senter and Dr. Juengst did was so very important:

As stated in their paper, it is all too often that dinosaur pathologies are overlooked in a newly discovered species in favor of describing the traits characteristic of the new species and not anything unusual or pathological to the particular specimen. What other amazing discoveries could we make about the life of the animal if we looked more closely for injuries and abnormalities?

The sheer number of injuries of this specimen (8 in total, all concentrated in the pectoral girdle and forelimbs) shows that it was leading a very active lifestyle in which the arms played an important role in prey capture. (One theory posited by the team is that the injuries may have been caused by a struggling prey item- another one is they were inflicted in a fight with a conspecific.) Additionally, the osteodysplasia shown in the left forelimb would have impacted its mobility in that arm, and therefore the Diloph must have favored its right forelimb to avoid causing pain in the other.

In summary, more carefully examining fossils for signs of injuries can tell a fascinating story about the lives that these animals led, as well as the healing processes in dinosaurs in comparison to modern reptiles, birds, and mammals.

In addition, my artwork has appeared in the following press releases on the article:PLOS Blog: http://blogs.plos.org/paleocomm/2016/02/24/what-a-pain-in-the-arms-a-record-breaking-number-of-injuries-in-a-theropod-dinosaur/ (It’s such an honor to see my artwork alongside that of Heather Luterman, an artist I’ve admired for over a decade now!)

Live Science: http://www.livescience.com/53832-jurassic-dinosaur-injuries.html

(Enough with the “finger” jokes, people…but that aside, a nice article.)

Without further ado, here are my *slightly* improved illustrations for the Senter et al.,2015 paper. Under each image, I will write briefly about the illustration as well as additional research and references used for each dinosaur. I worked on a pretty tight deadline for these images, so that’s why, in essence, they’re “not as good as they could be”. (Or is that my perfectionism speaking?)

Also, if anyone wants to see larger versions of these, please go to my page entitled “Art Gallery”. (You can click on the black box with horizontal lines above my name to expand the menu and see the respective link.)

Velociraptor mongoliensis. Proportions are based on Scott Hartman’s 2013 V. mongoliensis skeletal for the most part. (You can see Scott Hartman’s website here: http://www.skeletaldrawing.com/ )

The coloration for this particular reconstruction was inspired by a mix of Pied crows, Stellar’s sea eagles, and the facial skin present on Crested caracaras. The pale yellow of the display feathers is based on the research of Matthew Martyniuk, ( http://mpm.panaves.com/ ) in particular, that presented in his book “A Field Guide to Mesozoic Birds and Other Winged Dinosaurs”.

It’s quite likely that the feathers of most non-avian theropods would not have had many of the bright colors that we see in modern birds. Mainly, this is due to the fact that certain chemical pathways for synthesizing the pigments may not have evolved yet, having a much more recent origin. (At the origin of clade Neognathae, or perhaps even Neornithes, I cannot remember which at the moment.) It would also be due to structural limitations- only non-avian dinosaurs with feathers that have barbules, which can trap air pockets, would be able to produce iridescence, as well as vibrant blues and purples. Feather structure can also add to the vibrancy produced by carotenoids and other pigments. This is why the I also made the black and white on this Velociraptor particularly muted compared to modern birds- it seems likely that this non-volant species had a less complex feather structure than its flying cousins like Microraptor. (However, I cannot completely rule this out- a recent study (2015, Parsons & Parsons) suggested that juvenile Deinonychus may have been volant!)

In terms of things I would change about this drawing, if I illustrate V. mongoliensis again:

I would make the primary and secondary remiges overlap more accurately, as they do in modern avian wing folding. I’ve changed it to the proper configuration on some of the secondaries, but I should have continued it throughout the entire wing.

I would probably omit the feathers on the feet, and make them into overlapping scutate scales (which are repressed flight feathers- see Dhouailly, 2009). I made them feathered, because it’s quite likely that many Maniraptorans had feathered feet, given that it is the primitive condition. But when I think of how Velociraptor lived in a desert environment- the transition of the podotheca from feathers to scales could have been beneficial for thermoregulation in this species.

Parasaurolophus walkeri. In this reconstruction, I used Scott Hartman’s 2013 Parasaurolophus skeletal as a reference for the proportions. The banded and striped pattern on the tail and body was inspired by Bell’s 2012 research on hadrosaurid skin impressions. However, skin impressions for P. walkeri are still unknown, so this similarity is speculative.

I also gave it a speculative flap of skin on the corners of the mouth, as present in extant puffins. You’ll also the notable lack of “cheeks” as present in old reconstructions of this species- this is a direct nod to the theories of Jaime Headden on why all dinosaurs probably lacked such structures. The crest is made of thick keratin and serves as a colorful display structure, similar to how the bills of some extant birds are brightly colored. Otherwise, I felt like muted greens, browns, and beige was the best color scheme, to aid in camouflage.

I’m not sure if the unguals would have shown on the front feet- I’ve read at least one source online that says the unguals were covered in scaled skin, but I cannot find the paper that describes this. (Update…I’m pretty sure they were. Will need to edit this.)

Caudipteryx sp. References used included photographs of a specimen supplied to me by Phil Senter. I also based the proportions on Jaime Headden’s skeletal reconstruction of Caudipteryx sp. ( http://qilong.wordpress.com )

The published version had much, much shorter secondaries. I lengthened them on the advice of other paleoartists. To my untrained eye, it seems as though the primaries were quite long in this species (judging from the fossil), and could have even been longer than the secondaries. However, this could easily be a taphonomic artifact. If I were to illustrate this species again, I’d probably make the secondaries even longer than they are here, to fit with a more conventional look.

I’d also probably give it actual tarsal scutes instead of the more rounded scales that I gave it, to fit with what we know currently (again, see Dhouailly, 2009). I’d also probably make the tail feathers longer, as well as have the feathers hide the contours of the body even more.

Dilophosaurus wetherilli. For this particular reconstruction, I only used photos of skeletal mounts supplied to me by Phil Senter. (Unsure of what specimen(s) the mounts were based upon.) I also looked at Jaime Headden’s ( http://qilong.wordpress.com ) Dilophosaurus skull reconstruction, and used that as a reference for how to properly depict the crest.

Overall, this is probably my least favorite reconstruction out of all of them. That’s because, the more I look at it, the more it seems as though the feet and legs are overly long, and they’re also far too flexed. The head seems too small. Oh well, live and learn, eh?

Not a whole lot to say about this one. I made it scaled, since its descendants- the sauropods- were scaled as shown by skin impressions (including that of a titanosaur embyro), but there’s still a chance it was feathered or had some filamentous structures.

Color scheme somewhat inspired by Uromastyx lizards. The bright orange along the sides could be a display feature.

Thescelosaurus neglectus. I used a photograph of a skeletal mount provided to me by Phil Senter for the proportions.

Perhaps I gave this one *too* much of a Kulindadromeus vibe, after all, it’s only related to it in the fact that it’s an Ornithiscian, and that’s about as far as it goes, and it was also about three times larger. Nevertheless, I wanted to give it feathers, since it’s quite likely that it had them.

If I had to draw it again, though, I’d make the scale morphology less Kulindadromeus– like, since it’s highly unlikely they had such a similar scale pattern given how distantly related they are. I’d also position the legs a little bit more forward- it looks a bit as though its legs are too far back at the moment to properly balance it?

And yes, if you’re wondering- the quills on the back are a nod to the Saurian game (Currently in development).

Emily Willoughby: (Who serves as a constant source of inspiration for me, since I have watched her art progress over the years and she’s shared valuable knowledge about Maniraptorans!) http://emilywilloughby.com/

Studio Spectre (Stephen R. Moore), for a suggestion on negative space that helped tremendously! Also, for being a very inspiring artist. http://www.stephenmoorefineart.com/studiospectre/

To see the pages I’ve created (including Publications, About the Artist, and Contact), click the square with lines in the upper right hand corner in order to expand the menu, where you can find the links to those pages.

Right now I plan on using this website to share my (slightly) improved paleoart that I was able to publish for Phil Senter. I worked on a tight deadline for that project (Figure 5, “Resting Orientations of Dinosaur Scapulae and Forelimbs…”) so I was not able to add the small additions that I wanted to in that time frame.

In the future, you can expect to see paleoart that is exclusively for this website and will, hopefully, be a chronicle of my continued improvement, art-wise.

I also accept and encourage critique of my artwork by professional paleoartists. After all, I feel as though critique is the main thing that can help me improve my skills and so that I can see what (if anything), I’m doing wrong, and avoid those mistakes in the future. However, when critiquing please keep in mind that I’ve only been able to use the listed references (which are almost always in photograph form, since I live far away from most museums) and due to this, I probably miss important anatomical information in some of my illustrations. Nonetheless, I strive to be as accurate as possible and in the future, I’d love the opportunity to see more specimens in person so I can get a better idea of their anatomy. I also attempt to consistently stay up to date on theropod literature- but I’m likely to miss things, since again, this is a part time endeavor.

I also appreciate comments from the general public. Let me know your thoughts!